In boat and airplane navigation where electronic navigational devices are not employed, it is most usual to use nautical charts. These charts are typically large and require use of various mechanical instruments for plotting a course or locating one's position on the chart. Usually, protractors, compasses, parallel rules, straight edges and grease pencils are needed. The manner in which these instruments are used is well known and need not be explained here. For purposes of understanding the present invention, it is sufficient to point out that this system of navigating is generally cumbersome and unwieldly, particularly, for example, on small boats and in foul weather when the equipment is used outside. Not only are the charts large in size, plotting positions and courses on the charts with the various mechanical instruments is inconvenient. Misplacement or loss of the instruments is also a problem not to mention the rather extensive collection of the large chargs that must be maintained.